§ 1.1 Field of the Invention
This invention relates generally to the field of supramolecular chemistry and in particular to extended pi-conjugation of oligomers, such as aniline oligomers for example, in solution and in solid-state.
§ 1.2 Background Information
For hundreds of years, chemistry has largely focused on the behavior of molecules and their construction from constituent atoms leading to our present state of high confidence to tackle the construction of most any molecule, be it biological or designed, organic or inorganic, or monomeric or macromolecular in origin. During the last few decades, however, chemists have extended their investigations beyond atomic and molecular chemistry into the realm of “Supramolecular Chemistry.”
In general, supramolecular chemistry is the study of interactions between—rather than within—molecules. In other words, chemistry using molecules—rather than atoms—as constituent building blocks for structures beyond the atomic scale. Additionally, whereas traditional chemistry deals with the construction of individual molecules from atoms, supramolecular chemistry involves the construction of organizations of molecular entities on much larger length and size scales. Consequently, terms such as “molecular self-assembly”, “self-organizing” and “nanoscience” have become part of the supramolecular chemist's vocabulary. This is a rather new concept in chemistry, introduced by the 1987 Nobel Laureate in Chemistry, Dr. Jean-MarieLehn. (http://nobelprize.org/chemistry/laureates/1987/ or Lehn, J-M., Supramolecular Chemistry, VCH Weinheim, Germany 1995)
The pursuit of supramolecular assembly in electroactive organic conjugated materials has been the subject of much research recently. (See, for example: A. P. H. J. Schenning, P. Jonkheijm, F. J. M. Hoeben, J. van Herrikhuyzen, S. C. J. Meskers, E. W. Meijer, L. M. Herz, C. Daniel, C. Silva, R. T. Phillips, R. H. Friend, D. Beljonne, A. Miura, S. De Feyter, M. Zdanowska, H. Uji-I, F. C. DeSchryver, Z. Chen, F. Wurthner, M. Mas-Torrent, D. denBoer, M. Durkut, and P. Hadley, Synthetic Metals, 147, pp. 43-48, 2004; and F. Cacialli, P. Samori, and C. Silva, Materials Today, Vol. 4, Issue 2, pp. 24-32, 2004.) As can be appreciated, self-organizing, organic conjugated materials offer up the possibility of materials having highly desired functionalities that cannot appear from a single molecule or ion, such as those (e.g., optoelectrical functions) of polymers for example. Self-assembling supramolecular assemblies of oligomers have some advantages over polymers. One important difference is that the “reversibility” of such self-assembly provides Chemists with great architectural control over such materials at nanoscale levels. This is in contrast to the conventional design of molecular architecture in chemistry involving covalent bonds.
For example in solution for polymers, (See, O. T. Ikkala, L. O. Pietila, P. Passiniemi, T. Vikki, H. Hsterholm, L. Ahjopalo, and J. E. Osterholm Synthetic Metals, 84, pp. 55-58, 1997.) molecular interactions between complementary moieties of a conjugated material and solvent—such as hydrogen bonding—as well as other interactions for example, π-π stacking, may promote self-organization to such an extent that well defined, supramolecular structure(s) result. Further study of these interactions will undoubtedly lead to better understanding of the self-organizational processes involved in polymers and oligomers. (See, e.g., M. Muthakumar C. K. Ober, and E. L. Thomas, Science, vol. 277, p. 1225, 1977.)
A common problem encountered when processing organic, conjugated materials, is that such polymeric materials exhibit relatively low solubility in common organic solvents. When poor solubility is encountered, the polymer in the solution becomes coiled-up in terms of its backbone conformation, leading to unfavorable aggregation and entanglement problems. This results in undesirable functional properties, mainly due to the conformational defect. This problem is particularly acute with polyaniline (PANi), which is the parental polymer of aniline oligomers.
In an attempt to address some of the problems associated with the intractable nature of common conjugated polymers in solvents, research has been directed to the development of “pseudo-polymeric” materials from conjugated oligomers via supramolecular pathways. (See, for example, Z. V. Vardeny, A. J. Heeger and A. Dodabalapur, Synthetic Metals, Vol. 148, pp. 1-3, 2003; and V. F. Razumov, S. B. Brichkin, O. M. Pilugina, T. P. Karpova, S. Z. Vatsadze, D. A. Lemenovskii, M. Schroder, N. R. Champness, M. V. Alfimov, Russian Chemical Bulletin International Edition, vol 51 no.3, pp. 476-480, 2002.) One aim of these supramolecular approaches is to replace conjugated polymers with more soluble, well-defined conjugated oligomers which retain the desirable polymeric functional properties, such as high conductivity for example. Unfortunately, only limited success has been realized. (See, e.g., A. G. MacDiarmid and A. J. Epstein, Synthetic Metals, Vol. 69, pp. 85-92, 1995; and N. A. Loshkin, O. A. Pyshkina, V. B. Golubev, V. G. Sergeyev, A. B. Zezin, V. A. Kabanov, K. Levon, and S. Piankijsakul, Macromolecules, Vol. 34, pp. 5480-5486, 2000.)
Consequently, methods and materials which facilitate the development of these supramolecular approaches would represent a great advance in the art. Such methods and compositions of matter are the subject of the instant invention.